Method of fabricating a hub



April 26, 1966 J. s. OLES METHOD OF FABRICATING A HUB 5 Sheets-Sheet 1Original Filed May 24, 1961 m i m M 4 5 w imam is y H W 9 H mfl Y B 6 w3. m h. H J

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0 15071 QCT'G'IE ArronMsY J. S. OLES METHOD OF FABRICATING A HUB April26, 1966 Original Filed May 24, 1961 7/ W v 2 M1 #5 2M Z M! Z 2 k r: v 7e H April 26, 1966 5, QLES 3,247,584

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BY m 6.1115021, Selll e aC-raig Arrow/ans r: 3,247,584 Ice Patented Ap-26a 1966 3,247,584 METHOD OF FABRECATING A HUB John S. Oles, 15035Prevost Ave, Detroit 27, Mich. Original application May 24, 1961', Ser.No. 112,299, now Patent No. 3,178,952, dated Apr. 20, 1965. Divided andthis application June 15, 1964, Ser. No. 351,893

7' Claims. (ill. 29159.3)

This application is a division of my copending application Serial No.112,229 filed May 24, 1961 and now US. Patent 3,178,952.

This invention relates to a fabricated hub and more particularly to aunique hub structure which is formed, assembled and finish-machined inone stroke of a press, and to a method for producing fabricated hubs. V

Heretofore, in the production of hubs for use with pulleys and similarrotatable devices, such as gears and the like, it has been a commonpractice to form such hubs by casting from metals such as iron andsteel. Disadvantages of cast iron and steel structures, however, arethat they are of unduly high weight and of course do not have thestrength of forgings or stampings.

Hubs also have been formed by stamping components thereof and fasteningthe components together as by bolts or rivets. A-lso assembly has beeneffected by press fitting the bushing component of the hub into a boreof a flange member. Disadvantages of the pressed :and fastenedstructures reside in the numerous parts comprising the structures andthe necessity for assembling the parts, and fastening them together inseparate operations as by bolting, riveting or the like. Disadvantage ofstructures wherein the bushing is merely press fitted into the flangemember is that the bushing may be axially displaced from the flange.This requires that the press fitted bushing be brazed or welded intoposit-ion to assure its retention in place. This of course necessitatesan extra step which raises the cost of the item.

Accordingly a step forward in the art of fabricated hub constructionswould be provided by the production of a hub assembly wherein the partsare assembled and retained against axial as well as torsionaldisplacement from each other, in a single operation.

It is therefore an important object of the present invention to providea novel fabricated hub structure wherein the shaft engaging bushingthereof is retained against axial displacement from the flanged cupthereof by an interlocking relationship of the metal forming theseparts.

An additional object of the present invention is to provide a method forproducing a novel fabricated hub structure wherein the parts areinterlocked against axial displacement from each other by a uniquedovetailed interlocking relationship of the parts.

A further object of the present invention is to provide a novelfabricated hub structure comprising a split inner sleeve carried withina stamped cup, the parts being interlocked in dovetailed relationshipwith each other to resist axial displacement thereof, and wherein thesplit sleeve provides a keyway in the assembly.

A further object is to provide a method for die forming a fabricated hubstructure wherein an inner sleeve is locked into a dovetailed engagementwith an outer flange member by application of suflicient pressure uponthe parts to causethem to attain a state of plastic flow and assume theinterlocking dovetailed relationship and wherein all parts are pressmachined to finished dimension by a single press stroke.

Another object is to provide a method for press machining a fabricatedhub wherein the metal parts are simultaneously assembled, finished andwork-hardened in one stroke of a press to provide a structure havingsuperior gripping power when press fitted on a shaft.

Yet a further object of my invention resides in the provision of animproved method of press forming a fabricated hub having a uniquestrength pattern wherein thinner press-forged sections have greatertensile strength to provide a light-weight but strong hub structure.

Still another object of the present invention is to provide a method forfabricating a hub by press machining wherein the hub is completelyformed by one stroke of a press, the hub ends being flattened andsquared with the flange and the central bore being t med and squaredwith the flange. I

Another object of my invention is to provide an improved method ofmaking a stamped press-forged hub wherein an outer tapered member has asubstantially straight inner axial surface and tapered outer surfaceadapted to be press formed against the inner surface of a die member,the axial extent of contact of the outer surface with the inner surfaceof the die member varying dependent on manufacturing tolerances of thefabricated parts being assembled.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

In the drawings:

FIGURE 1 of the drawings is a section View of a die drawn flanged cuputilized in producing the novel hub structure of the present invention;

FIGURE 2 is a bottom plan viewof a bushing forming a part of thefabricated hub structure of the present invention;

FIGURE 3 is a section view taken along line 33 of FIGURE 2;

FIGURE 4 is a top plan view of a circular fabricated hub structure madein accordance with the present invent-ion;

FIGURE 5 is a section view taken along line 5-5 of FIGURE 4;

FIGURE 6 is a section view taken along the line 66 of FIGURE 5;

FIGURE 7 is a section view through a fabricating die utilized to formhubs in accordance with the present invention, showing a bushinginserted into a flanged cup prior to application of pressure;

FIGURE 8 is a section view similar to FIGURE 7 after the die has movedto force the parts into dovetailed interlocking relationship with eachother;

FIGURE 9' is a perspective view of a' fabricated hub structure made inaccordance with the present invention and having a'keyway therein;

FIGURE 10 is a top plan view of a press-machining die employed toassemble end form a hub similar to'that shown in FIGURE 9;

FIGURE 11 is a section view taken along the line 1'1-11'of FIGURE 10,and

FIGURE 12 is a fragmentary sectional view illustrating. the approximatevariations of hardness of the tapered wall of the cup member in thecompleted hub structure.

Before explaining the present invention indetail, it is to be understoodthat the invention is not limited in its application to the details ofconstruction and arrangement of parts illustrated in the accompanyingdrawings, since the invention is capable of other embodiments and ofbeing practiced or carried out in various ways. Also, it is to beunderstood that the phraseology or terminology employed herein is forthe purpose of description and not of limitation.

Broadly, the present invention relates to a'hub structure of uniqueconfiguration and to a method for making the same wherein the innersleeve of the hub and the outer flanged cup-like part thereof areinterlocked with each other against axial displacement by a uniquedovetailed relationship of the parts by a die or press forming operationwherein the parts are subject to sufficient pressure so that they attaina state of plastic flow to be deformed into the dovetailed interlockingrelationship with each other.

As shown in FIGURE 1 of the drawings, a stamped metal cup 10 is formedfrom a circle of sheet steel having an original thickness equal to thethickness of radially extended flange 12. As the plate is drawn outduring the stamping or dieing operation, the wall 14 defining a cup-likestructure is gradually reduced from the thickness of flange 12 to thethickness at the inwardly extending flange 16. The press operation iseffected utilizing a die of substantially straight cylindricalconfiguration having a diameter equal to the inside diameter of the wall14. The flange element 12 is retained on a die along the surface 18 upto the radius 20. From the inner radius 20 to the outer radius 22 theouter portion of the wall 14 is not supported and accordingly during thepressing and thinning operation it develops an inward taperalong thearea indicated by the arrow 24.

The flange 12 is provided with tapped holes 15 for attachment as bybolting to a pulley or the like.

As shown in FIGURES 2 and 3 of the drawing a bushing 25 of generallytubular configuration having a substantially cylindrical bore 26 and aparallel, cylindrical outer surface 28 is provided with a preformedflange 30. The outer surface 28 is of a diameter very slightly smallerthan the inside diameter of the cup defining wall 14 to slidably fittherein.

The finished hub assembly is illustrated in FIGURES 4, and 6 and themethod by which the sleeve 25 is retained within the stamped metal cupis illustrated in FIGURES 7 and 8.

As shown in FIGURES 7 and 8 a forming die for use in the method of thepresent invention includes a central pin member 32 and an annularsupporting die block 34 having a cylindrical slightly tapered recess 36coaxially thereof for receipt of the central die pin 32. The die pin 32is provided with a shoulder 38 and as shown in FIGURE 7 the formed cup10 of the FIGURE 1 is fitted down over the pin 32 to rest upon theshoulder 38, the flange 12 of the stamped metal cup 10 resting upon ahorizontally disposed shoulder 40 of the die block 34.v The annularbushing 25 of FIGURES 2 and 3 is then inserted over the pin 32 withinthe cup 10. Thereafter an upper die member 42 having a central aperture44 adapted to fit around the pin 32 is moved downwardly to the positionshown in FIGURE 8.

As the die is moved downwardly, sufiicient pressure is developed toforce the sleeve 25 down into the cup 10 so that both the metal in thesleeve and the metal of the cup attain a state of plastic flow. Themetal in wall 14 of the stamped metal cup 10 at the radius 22, FIG- UREl, is forced outwardly to be restrained by the die member 34 so that itassumes a cylindrical outer configuration. During this operation themetal of the sleeve is also caused to be thickened and forced outwardlyfollowing the inner contour assumed by the wall 14 of the stamped metalcup 10. Thus a dovetailed interlock 45 is formed between the partswhereby they are there after permanently retained against axialdisplacement from each other. It will of course be apparent that aslight taper such for example as approximately .005" per inch should beprovided between the outer surface of the cup 14 and the inner surfaceof the cavity in the die 34, and between the inner surface of the sleeve25 and the pin 32 to permit release of the finished parts from the dieas is customary in such manufacturing operations.

It should be pointed out that during this one stroke of the press, theparts are not only assembled but they are also press machined to finishdimensions. Thus the entire hub assembly is completely formed by onestroke of the press, the hub ends are aligned flat and square with theflange, and the central bore is aligned true and square with the flange.Also, the bore is sized out to an accurate dimension.

Attention is directed to the fact that as the upper die member 42 ismoved downwardly toward the position shown in FIGURE 8, the sleeve 25which projects into the substantially straight inner bore in the cup 10expands the cup into contacting relation relative to the inner face ofthe die. The degree or extent of this axial deformation of the outertapered surface of the cup into contacting relation with the innersurface of the mold is dependent upon the manufacturing tolerances ofthe sleeve and cup. For example if the dimensions of the sleeve and cupare on the high side of the permissible tolerances, the engagement ofthe outer or tapered surface of the sleeve with the inner surface of themold will extend axially a greater distance than will be the case if thetolerances are on the low side. It is considered desirable to insureadequate strength that the outer tapered surface of the cup be deformedto engage the inner surface of the mold throughout approximately 50% ofits axial length. A considerable safety factor is thus provided topermit a reasonable variation in dimensions of the parts utilized in thefabrication of my improved hu'b.

It should also be pointed out that during the assembly process, themetal of both the sleeve 25 and the stamped metal cup 10 is cold workedor work hardened and its yield point or elastic limit is thereby raisedso that its gripping power under conditions of press fit on a shaft isincreased double or more over a comparable sized hub made of low carbonsteel in its original soft condition.

With my improved method of fabricating hubs, the hardness of the metalof the Wall 14 of the cup 10 varies dependent upon the pressure to whichvarious portions are subjected. This is illustrated approximately inFIG- URE 12 wherein the numerals indicate varying degrees of hardness onthe Rockwell B Scale ranging from approximately 66 to approximately 91.This variation in hardness is accompanied by a variation of tensilestrength of various portions of the completed hub, ranging fromapproximately 60,000 to 90,000 psi. as the degree of hardness increases.This unique feature results in an improved hub having desirable strengthdistribution characteristics.

TORSIONAL INTERLOCK While the above described operation has provided aunique method of retaining two interfitted hub parts against axialdisplacement, rotary or torsional displacement of the parts with respectto each other is also provided by the one stroke of the press during theassembly and press machining operation. This torsional slippingresistance can be imparted by several means; however, for purposes ofconciseness, two features will be described. As shown in FIGURE 6, fourtorsional interlocks are provided by means of cooperating grooves formedbetween the outer periphery of the outer surface 28 of the bushing 25and the inside of wall 14 of the stamped metal cup 10. To provide theseinterlocking grooves, relief portions are provided in the die member 34at the points 46, FIGURE 8. Thus during the pressing operation, themetal of the cup 10 is permitted to flow outwardly into the reliefportions 46 as shown in FIG- URE 6 to provide small bosses 48 at theinner radius 20, FIGURE 1, of the cup 10. As the metal of the cup atradius 20 flows outwardly, the metal of'the sleeve 25 follows it to forman interlocking projection 50 on the outer surface 28 of the bushing 25that projects into a groove 52 formed on the inner surface of the wall14 of the metal cup 10 as the metal thereof moves outwardly into therelieved portion 46 of the die member 34.

Thus the parts of the hub assembly are restrained against axialdisplacement from each other and also restrained against torsionaldisplacement :from each other.

Another method of restraining the sleeve 25 against torsionaldisplacement with respect to the stamped metal cup comprises forming aknurl on the outside of the sleeve 25 so that when the sleeve is pressedinto the cup incold plastic flowing relation therewith, the knurl isimparted to the inner side of the wall 14 of the cup 10 to form aninterlocking engagement.

Still another method of restraining the sleeve 25 against torsionaldisplacement with respect to the stamped metal cup 10 comprises formingon the exterior of the sleeve any configuration of projectionsequivalent to the knurl mentioned above. Thus one or more knurl-likeproyections can be utilized on the outer surface of the bushing toimpart their configuration to the wall 14 of the cup Iii when the piecesare pressed together.

A RELATED.ASPECT OF THE PRESENT INVENTION The foregoing discussion hasrelated to the use of a solid bushing being pressed into an outerstamped metal cup in such a manner that the parts are locked indovetailed relationship and thereby prevented from being axiallydisplaced from each other. However, it is also to be included within thescope of the invention to use a split bushing and thus provide a methodof making a keyway during the stamping operation. It should be pointedout that the dovetailing feature described above is utilized to hold thesplit bushing in place in thesame manner as for the solid bushingdescribed and the torsional displacement resistance is also provided asdescribed. However, in this aspect of the invention, a die pin having akey formed axially along its periphery is utilized over which a splitbushing is positioned for the forming operation.

To further illustrate this embodiment of the invention, reference willnow be made to FIGURES 9, 10 and 11 of the drawings which illustrate theformation of a hub having a keyway formed in the inner wall or borethereof, and having a dovetail interlock as described above. As shown inFIGURES l0 and 11, a central die pin 54 is provided with an axiallyextending recess 56 in its periphery, into which a key 58 is secured. Apressed cup 60 is first positioned Within a cavity 62 of a die member 64with the central die pin 54 projecting upwardly therethrough. The splitbushing 65 is then positioned upon the central die pin 54 in straddlingrelationship to the key 53. Thereafter, in the manner described inFIGURES 7 and 8, the upper press member 67 is moved downwardly undersuflicient pressure to cause the bushing and cup to attain a plasticflow relationship to form the dovetailed interlock 68 as shown in FIGURE11 of the drawings. As shown by the broken perspective view of FIG- URE9, a keyway 70 is formed within the bore of the hub assembly 72 when thekey 58 of the die pin 54 is removed after the pressing operation iscomplete.

As in the foregoing embodiment of the invention, the split bushing 65 isrestrained against torsional movement with respect to the pressed cup 60by means of projections 74 formed by the metal of the cup 66 flowinginto relief portion 76, FIGURE 11, formed within the cavity 62 of thedie 64. This causes the same type of interlocking relationship betweenthe bushing 65 and the cup 69 as is shown in the parts illustrated inFIGURE 6.

Thus in this embodiment of the invention, by one stroke of a press, ahub assembly is formed complete with a keyway wherein the bushing andcup components of the hub assembly are locked into dovetailed engagementwith each other and thus restrained against axial displacement and arefurther locked into engagement with each other against torsionaldisplacement.

6 MATERIALS OF CONSTRUCTION The hub assemblies made in accordance withthe present invention are fabricated from sheet steel such as hot rolledplate which, under the pressures developed in a press operation iseffective to achieve a state of plastic flow to be formed into adovetailed interlocking relationship and to have all parts and surfacesaligned with each other during said pressing operation. Although hotrolled steel has been utilized, it is to be considered within the scopeof the invention to utilize other metals displaying similar plastic flowproperties.

ADVANTAGES OF THE PRESENT INVENTION In accordance with the presentinvention, a hub assembly of superior gripping power, when press fittedon a shaft, is provided wherein the parts are constrained against axialdisplacement and torsional displacement with respect to each other in asingle stroke of a press. Additionally, the parts become work hardenedduring the plastic flow in the press. Still further, the parts arecompletely finish machined by the press operation, all parts being flatand square and in proper aligned relationship of each other.

I claim:

1. In a method of producing a fabricated hub, the steps of pressing aplate of metal into a cup-like shape wherein the wall of the cup becomesthinned and the outer surface tapered inwardly as the metal stretchesduring the pressing operation, positioning the cup in a retaining diehaving a cylindrical side wall and solid cylindrical core, so that theouter tapered surface of, the wall of the cup has a portion out ofengagement with the die, and pressing a cylindrical bushing into saidcup around said core under pressure sufiicient to cause cold plasticflow of said bushing and the wall of said cup to deform said bushingoutwardly and carry said wall of said cup out against said cyiindricalside wall of said die and interlock said bushing and said side wall ofsaid cup in dovetailed engagement against axial displacement.

2. In a method of producing a fabricated hu-b the steps of pressing aplate of metal into a cup-like shape wherein the wall of the cup isthinned and the outer surface tapered inwardly as the metal stretchesduring the pressing operation, positioning the cup in a retaining diehaving a cylindrical side wall and a solid cylindrical core, andpressing a cylindrical bushing into said cup around said core underpressure sufiicient to cause cold plastic flow of said bushing and saidside wall of said cup to deform said side Wall and said bushing intodovetailed, interlocking engagement, wherein the inner and outer wallsof the assembly are of straight cylindrical configuration and coaxialalignment.

3. In a method of producing a fabricated hub, the steps of pressing aplate of metal into a cup-like shape wherein the wall of the cup isthinned and tapered inwardly as the metal stretches during the pressingoperation, positioning the cup in a retaining die having a cylindricalside Wall and cylindrical core, and pressing a cylindrical bushing intosaid cup around said core under pressure sufficient to cause coldplastic flow of said bushing and said side wall of said cup to deformsaid side wall and said bushing into dovetailed, interlockingengagement.

4. In a method of press-machining a fabricated hub having a keyway inthe inner bore thereof, wherein a plate of metal is pressed into acup-like shape with the wall of the cup becoming thinned and the outersurface tapered inwardly as the metal stretches during the pressingoperation, the steps of positioning the cup in a retaining die having aside Wall and solid cylindrical core having a key therein with the outersurface of the cup out of engagement with the die, and pressing a splitbushing into said cup around said key and said core under pressuresuflicient to cause cold plastic flow of said bushing and the wall ofsaid cup to force said bushing outwardly and carry said wall of said cupout against said side wall of 7 said die and interlock said bushing andsaid side wall of said cup in dovetailed engagement against axialdisplacement.

5. The method of producing a fabricated hub comprising the steps ofpressing a plate of metal into a cuplike shape wherein the wall of thecup becomes thinned and the outer surface tapered inwardly as the metalstretches during the pressing operation, positioning the cup in aretaining die having a substantially cylindrical side wall and a solidcylindrical core, so that the outer tapered surface of the wall of thecup has a portion out of engagement with the die, and pressing acylindrical bushing into said cup around said core under pressuresufficient to cause cold plastic flow of said bushing and the wall ofsaid cup to deform said bushing outwardly and carry said wall of saidcup out against said cylindrical side wall of said die over a portion ofthe axial length of the cup and interlock said bushing and said sidewall of said cup in dovetailed engagement against axial displace ment,the extent of axial contact of the wall of the cup with the side Wall ofthe die varying dependent upon the dimensional tolerances of the cup andbushing, the higher the dimensional tolerances of the cup and bushingthe greater the extent of axial contact between the bushing and the sidewall of the die.

6. The invention defined in claim 5 wherein the hardness of the wall ofthe cup and the bushing on the Rockwell B Scale varies to provideincreased tensile strength in areas of reduced cross section.

7. In a method of producing a fabricated hub the steps of pressing aplate of metal into a cup-like shape wherein the wall of the cup isthinned and the outer surface tapered inwardly as the metal stretchesduring the pressing operation, positioning the cup in a retaining diehaving a cylindrical side wall and a solid cylindrical core, andpressing a cylindrical bushing into said cup around said core underpressure sufiicient to cause cold plastic flow of said bushing and saidside wall of said cup to deform said side Wall and said bushing intodovetailed, interlocking engagement, wherein the outer wall of thebushing and the inner wall of the cup are press formed into intimatecontact, and the outer wall of the cup is deformed radially outwardlyinto intimate contact with the inner surface of the die over a portionof its axial length, the extent of axial contact of the outer wall ofthe cup with the inner surface of the die being dependent on thedimensional tolerances of the cup and bushing.

References Cited by the Examiner UNITED STATES PATENTS 1,902,222 3/1933Eksirgian 29l59.3 2,143,176 1/1939 Welsmiller.

2,232,973 2/1941 Rood.

2,497,242 2/1950 Sprouse 29--159.3 X 2,509,711 5/1950 Williams 29159.3 X2,869,219 1/ 1959 Quinn.

FOREIGN PATENTS 985,930 3/1951 France.

WHITMORE A. WILTZ, Primary Examiner.

I. D. HOBART, Assistant Examiner.

1. IN A METHOD OF PRODUCING A FABRICATED HUB, THE STEPS OF PRESSING APLATE OF METAL INTO A CUP-LIKE SHAPE WHEREIN THE WALL OF THE CUP BECOMESTHINNED AND THE OUTER SURFACE TAPERED INWARDLY AS THE METAL STRETCHESDURING THE PRESSING OPERATION, POSITIONING THE CUP IN A RETAINING DIEHAVING A CYLINDRICAL SIDE WALL AND SOLID CYLINDRICAL CORE, SO THAT THEOUTER TAPERED SURFACE OF TGHE WALL OF THE CUP HAS A PORTION OUT OFENGAGEMENT WITH THE DIE, AND PRESSING A CYLINDRICAL BUSHING INTO SAIDCUP AROUND SAID CORE UNDER PRESSURE SUFFICIENT TO CAUSE COLD PLASTICFLOW OF SAID BUSHING AND THE WALL OF SAID CUP TO DEFORM SAID BUSHINGOUTWARDLY AND CARRY SAID WALL OF SAID CUP OUT AGAINST SAID CYLINDRICALSIDE WALL OF SAID DIE AND INTERLOCK SAID BUSHING AND SAID SIDE WALL OFSAID CUP IN DOVETAILED ENGAGEMENT AGAINST AXIAL DISPLACEMENT.